Missing on one cylinder

Reply Subscribe

Thread Tools

Search this Thread

Nov 1, 2025 | 07:05 PM

Mefordz

Thread Starter

1st Gear

Joined: Nov 2025

Posts: 1

Likes: 0

Missing on one cylinder

11 expedition, 5.4, missing on cyl 3, replaced coil, plug, injector, 125 lbs compression.

Bought it site unseen from wrecker serv., 257,000 miles.

Been rode hard, put up wet.been messing with it for 2 weeks now,swapped coils, swapped injectors, plug looked good, but replaced it anyway.

Wiring seems good,coil fires, injector seems to work right.

I'm not good with fuel infection, prefer carbs anyway.

Have I missed any steps?

I don't own a real scanner, just little code readers.
Don't know anyone that owns one either.

Nov 2, 2025 | 06:49 PM

Beechkid

Moderator

Joined: Aug 2002

Posts: 6,100

Likes: 380

From: Southern California

Doa leakdown test on that cylinder.... you will know for sure then.....

Nov 6, 2025 | 11:44 AM

meborder

Moderator

Joined: Jul 2011

Posts: 6,508

Likes: 657

From: Sioux Falls Area

I’d be willing to bet it spit out a cam follower.

If you can wedge open the CMCV in the intake, it might run on all 8.

#3 and #7 are the two most common cylinders to loose a follower.

Nov 6, 2025 | 03:07 PM

Johnny Paycheck

Fleet Mechanic

Joined: Jul 2019

Posts: 1,314

Likes: 312

Quote:

I'm not good with fuel infection, prefer carbs anyway.

Don’t let that curve you. Fuel, spark and compression need to be on the up and up for an engine to run right.

Figure that out before firing the Random Parts Cannon at this.